Scientists
discover 'second brain' in the stomach
Scientists are claiming to
have discovered a second brain - in the human stomach.
The breakthrough, involving
experts in the US and Germany, is believed to play a major part in the
way people behave.
This 'second brain' is made
up of a knot of brain nerves in the digestive tract. It is thought to
involve around 100 billion nerve cells - more than held in the spinal
cord.
Researchers believe this belly
brain may save information on physical reactions to mental processes and
give out signals to influence later decisions. It may also be responsible
in the creation of reactions such as joy or sadness.
The research is outlined in
the latest issue of German science magazine, Geo, in which Professor Wolfgang
Prinz, of the Max Planck Institute for Psychological Research in Munich,
says the discovery could give a new twist on the old phrase "gut
reaction".
He said: "People often
follow their gut reactions without even knowing why, its only later that
they come up with the logical reason for acting the way they did. But
we now believe that there is a lot more to gut feelings than was previously
believed."
Professor Prinz thinks the
stomach network may be the source for unconscious decisions which the
main brain later claims as conscious decisions of its own.
The second brain was rediscovered
by Michael Gershorn, of the University of Colombia in New York, after
it was forgotten by science. He says it was first documented by a 19th
century German neurologist, Leopold Auerbach.
He discovered two layers of
nerve cells near a piece of intestine he was dissecting. After putting
them under the microscope he found they were part of a complex network.
Recent research has already
raised the idea that many reactions may be made in the stomach. Benjamin
Libet, of the University of California found the brains of volunteers
asked to raise their arms only registered activity about half a second
after the movement had been made. He believes his work implies another
part of the body may have been involved in making the decision.
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